Variable area rudder



Sept. 26, 1961 N. D. STOKER 3,001,592

VARIABLE AREA RUDDER Filed Jan. 14, 1960 2 Sheets-Sheet l A's/s an 0.Szoler' M ,W; M21575.-

3,001,502 VARIABLE AREA RUDDER Nelson D. Stoker, 416 Sheridan Road,Keuilworth, Ill. Filed Jan. 14, 1960, Ser. No. 2,412 11 Claims. (Cl.114-167) This invention relates to a rudder, and more particularly to arudder whose area may be automatically adjusted in accordance with thespeed of a boat, plane or other device controlled thereby to provideeffective steer-' ing characteristics throughout the speed range of thevehicle or device.

Heretofore, rudder steered craft, and particularly craft capable oftraveling at relatively high speeds, have had undesirable operatingcharacteristics, in that a small rud der area has been required tocompensate for the increased effect of the fluid medium onthe steeringsurfaces at the higher speeds, while this small rudder area has beeninad equate for control at lower speeds. The range of speeds availablewith power propelled craft makes an acceptable compromise in rudder areaimpracticable, since such an increase in rudder size is dangerous athigh speeds and relatively ineflective at low speeds. Although a rudderaffording detent controlled adjustment of its action at a predeterminedhigh speed level has been devised, such a rudder is also anunsatisfactory compromise and is both complex and difiicult to adjustand control.

The present invention resolves these problems by means of a rudderconsisting essentially of rudder sections pivoted together about ahorizontal axis and in parallel planes, with one of the sections beingprovided with vanes which, at higher speeds, lift it into a foldedposition with respect to the other section to decrease the effectivearea of-the rudder. As a result, the steering surface can be.

lifting action of the ambient medium on the vanes of the pivotedsection. The vane, or vanes, thus assume a position -parallel to thepropeller slip stream, or at a slight inclination such as to preventvibration at relatively high speeds while exposing a relatively largevane area at lower speeds to afiord the said lifting action, and thesections may be 'providedwith slot and pin means for guiding andlimiting their relative movement.

Accordingly, it is an object of the present invention to provide anadjustable rudder efiective to steer craft in water or air throughout awide range of operational speeds. A

Another object of the invention is to provide a rudder as describedwhich afiords safety and efliciency of control at high speeds and lowspeeds, as well as intermediatespeeds, in a completely automatic manner.

' Another object of the invention is to provide a rudder whose area .isautomatically variable and which is simple, efiicient and foolproof.

Another object of the invention is to provide a rudder of multiple and,overlappingelements whose relative positions arecontrolled, by theweight of the elements or otherwise, in accordance with the speed atwhich the rudder is moved through an ambient medium.

- Another object of the invention is to provide a rudder havingoverlapping plates horizontally pivoted to vary the area of the rudderby raising or lowering one of the plates. Another object of theinvention is to provide a rudder F ice as described having a sectionwhose position is varied with respect to another section by means of avane movable toward alignment with the slip stream as speeds increase.

Another object of the invention is to provide a vane or lift means forthe rudder as described which is effective to reduce cavitation at highspeeds.

Another object of the invention is to provide a multiple section rudderas described'having means for guiding and limiting the relative movementof the sections.

Yet another object of the invention is to provide a rudder havingmaximum efliciency at all speeds without any need for thought or efforton the part of the operator.

Other objects and advantages of the invention will become apparent asthe description proceeds in accordance with the drawings in which:

On the drawing:

FIGURE 1 is a side elevational view of a rudder according totheinvention in combination with a power propelled boat;

FIGURE 2 is an enlarged side elevational view of a rudder according tothe invention, and showing the low speed position thereof indot-and-dash;

FIGURE 3 is a horizontal sectional view taken along the line III--III ofFIGURE 2;

FIGURE 4 is a front end view of the structure shown in FIGURE 2;

FIGURE 5 is a side elevational view of another embodiment of the rudderof the invention in combination with a power propelled boat; FIGURE 6 isan enlarged side elevational view of the rudder shown in FIGURE 5, withthe low' speed position boat 11 powered by a propeller 14. Although therudder is thus shown in combination with a beat, it will be understoodthat it may also be used to great advantage with other vehicles anddevices which are rudder steered, including aircraft.

The rudder 10includesa rudder section 12 fixedly secured to a steeringpost 15 for pivotal movement about a vertical axis, a self-adjustingrudder section 16 horizontally pivotedfor coplanar movement with therudder section 12 around a pivot point or lug 18, and a vane structure20 secured to the rudder section 16 for automatically varying theposition of the section 16 with respect to the section 12 in accordancewith the speed of the boat 11.

The rudder section 12 has an area designed as adequate, proper and safefor controlling the boat 11 at cruising speeds or relatively highspeeds, in accordance with the understanding of those skilled in theart. This area is generally inadequate to control the boat properly atrelatively low speeds, and in fact, boats designed to travel at highspeeds are virtually uncontrollable at low speeds, such as 5 miles perhour, due to the described relatively small rudder area in proportion tothe hull.

The rudder section 16 has a configuration complemen tary to that of therudder section 12, and in the embodiment shown is formed of plates 22and 24 secured by peripherally spaced studs or rivets 26, 28, 30 and 32in parallel, spaced apart relationship such as to fold in tion shown inFIGURE 2, is in substantial registration with the section 12 with therivets 26 through 32 being disposed in peripheral alignment with therudder section 12, the plates 22 and 24 preferably being cut awayadjacent their forward portions to accommodate the socket portion 34 ofthe rudder section 12, as shown by reference numeral 35. In thedescribed uppermost position, the sections 12 and 16 have a projectedarea, preferably corresponding to that of the section 12 alone.

The vane'structure 20 onthe rudder section 16 is formed to elevate thesaid section 16 from the low speed position shown in dot-and-dash inFIGURE 2 to the high speed position shown in solid line, in FIGURE 2,and is aligned in "a position approaching a parallel relation with theslip stream from the propeller 14, in the high speed position, orpreferably at a slight upward inclination toward the front of the rudderso as to maintain a constant lifting action on the section 16 andsimultaneously to eliminate vibration. The vane structure 20 is shown asbeing formed of individual vanes 36 and 38 each having inner downwardlyturned flanges such as the flange 40 for the vane 38 secured by rivetsor the like 42 and 44 to the respective plates 22 and 24. It will beappreciated that the configuration of the vane structure 20 may bevaried in accordancewith variations in the type of craft with which therudder is used and with the complexity of the keel design or the like,the structure shown having a substantially ovoid, planar configurationwith a reduced width at the front portions thereof and leading edges '46and 48 tapered rearwardly so that the vane may bite easily into thewater. preferably has trailing edges 50 and 52 which are inclinedforwardly for hydrodynamic purposes,'as will be appreciated by thoseskilled in the art.

Although the vane structure 20 is shown as located adjacent the bottomof the rudder section 16, it may also be aligned in other positions,such as to cooperate with the pivot 18 to afford an effective liftingaction.

The pivot 18 desirably is located at the front bottom corner of therudder section 12, such that the rudder section 16 may have a lowermostposition as shown in dotand-clash in FIGURE 2. In order to define theuppermost and lowermost positions shown in solid line and dot-anddashrespectively, arcuate slots such as the slot 56 may be formed in theplates 22 and 24 to receive a guide pin 58 having heads 60 and disposedat a suitable radius from the pin 18. The envelope afforded by theplates 22 and 24 may move upwardly without interference around therudder section 12 as a result of the absence of rivets such as therivets 26 through 32, to the solid line position, and the pin 58 maycoact with the lower ends of slots 56 to afford a stop at the saiduppermost position. Likewise, the upper ends of the slots 56, as shownin dotted line in FIGURE 2, serve as a stop to prevent excessivedownward movement and forward movement of the section 16.

With the section 16 in its lowermost position, the bottom edge 62 of thesection 16 becomes the front edge thereof, with the vanes 36 and 38disposed at an oblique angle with respect to the slip stream from thepropeller 14. Increases in the speed of the boat, however, act uponthese surfaces to elevate the section 16 to its uppermost position, asdescribed, and also vary the angular relation of the section 16 to thesection 12 in accordance with the speed of the boat, automatically andwithout any necessity for human intervention. Thereby, accidents causedby errors in judgment on the correct amount of rudder area areeliminated.

As hereinabove indicated, the pivot point 18 is preferably located atthe lower front portion of the rudder 12, but it will be appreciatedthat other locations could be provided to vary the action of the section16. Variation in this action could also be afforded by varying the The,vane structure 20 also hull of the boat 72 beneath the propeller74'thereof. It-

will, be seen that the rudder section 70 defines a suitable air foil orhydrodynamic foil tapering and converging rearwardly from the relativelywide front portion 68, and having a generally torpedo-like crosssectional outline as also understood by those skilled in the art. Therudder section 70 is bifurcated from the rear-edge 76 thereof to definea coplanar slot 78 extending vertically therethrough and receiving asingle piece rudder section 80 pivotally connected to the rudder section70 by a pivot pin 82 corrmponding to the pivot pin 18 in the firstembodiment of the invention.

A vane structure 84 is formed at the bottom of the rudder section 80 inintegral relationship therewith, preferably so as to, be disposed inparallel abutting engagement with the bottom edge 86 of the ruddersection 70 and in parallel alignment with the slip stream from thepropeller 74 in the uppermost position of the section 80 shown in solidline in FIGURES 5 through 8.

In order to limit the pivotal movement of the section 80 around thepivot point 82, slot and pin means similar to those of the firstembodiment are utilized including of the pivotally mounted section berelatively less than,

a pin 88 extending through the rudder section 70 in preferablyhorizontal alignment with the pin 82, and received in an arcuate slot 0in the plate formed about a radius defined by the spacing of the pin 88from the pin 82. Thus, the lower end of the slot 90 may serve as a stopdefining the uppermost position of the plate 80 and the upper end of theslot 90 may act as a limit or stop to deline the lowermost position ofthe plate 80. As seenin FIGURE 6, this lowermost position may beinclined slightly less than ninety degrees from the uppermost positionof the plate 80.

Since the vane 84 is formed integrally on the bottom edge of the plate80, it afiords a continuous surface, as contrasted with the splitsurface afforded by the sections 36 and 38 of the vane 20 of FIGURES 1through 4. Consequently, the vane 84 may have a somewhat smaller totalwidth than the vane 20, and is otherwise similarly dimensioned andconfigured in relation to the weightof the plate 80 to provide a desiredlifting action which varies automatically with the speed of the vesselto pivot the section 80 into registered alignment within thebifurcatedsection 70 at cruising speeds or relatively high speeds of the boat 72.

Although the pivotal sections 16 and 80 are shown as having adimensional outline substantially corresponding to that of the ruddersections 12 and 70 to which they are pivotally secured, it will beunderstood that variations in this particular construction will beafforded within the scope of the invention. Thus, for example,particular conditions may require that the projected area or greaterthan, that of the rudder to which they are secured. Again, multiplepivoting action may be afforded by the provision of secondary sections(not shown) pivotally secured to pivotally mounted sections such as thesections 16 and 80. Also, the respective sections may be slidablymounted for relative movement by means of vanes positioned on the lowersections.

There has thus been providedpan expandable rudder of exceptionallysimple construction whose area is variable directly proportionally tothe speed of the vessel to which the rudder is secured, and inaccordance with the nature of the medium through which the vessel moves,the

weight or other biasing factor inherent in the pivotally mounted sectionof the rudder, and the construction of the vane acting as an elevatorfor the said pivotally mounted section. The vane acts to reducecavitation effects, and because no manual or other such adjustment isrequired, the device has extremely long wear characteristics, and isalso entirely safe and reliable; It therefore has application in a widevariety of situations, and in fact, may be advantageously used in anycraft or device which is steerable in a fluid medium.

Although I have herein set forth and described my invention with respectto certain specific principles and details thereof, it will beunderstood by those skilled inthe art that these may be varied withoutdeparting from the spirit and scope of the invention as set forth in thehereunto appended claims.

I claim as my invention:

41. A variable area rudder comprising a first rudder section, a secondrudder section connected to the first rudder section for pivotalmovement in variably lapping relationship with the first section about ahorizontal axis and in a plane parallel to the first rudder section,steering means on the first rudder section for turning said rudder abouta vertical axis and means responsive to fluid pressure on said secondrudder section for varying its pivotal position relative to the firstrudder section in accordance with the rate of movement of the rudderrelative to an ambient fluid medium.

2. A variable area rudder comprising a first rudder section, a secondrudder section connected to the first rudder section for pivotalmovement in variably lapping relationship with said first rudder sectionand about a horizontal axis in a plane parallel to the first ruddersection, Steering means on the first rudder section for turning saidrudder about a vertical axis, and a vane on said second rudder sectionresponsive to fluid pressure and configured and positioned to pivot saidsecond rudder section relative to said first rudder section inaccordance with the relative rate of movement of the rudder through afluid medium and the resultant fluid pressure on said vane.

3. A variable area rudder comprising a first rudder section, a secondrudder section pivoted to said first rudder section in variably lappingrelationship and for movement in a plane parallel to said first ruddersection, said second rudder section being configured and dimensioned toprovide a control area for the variable area rudder substantiallycorresponding to that of the first rudder section in an uppermostposition of the second rudder section and movable to a lowermostposition wherein the control area of the variable area rudder isincreased by a predetermined ratio for control of a craft or otherobject at low speeds, and vane means on said second rudder sectionresponsive to fluid pressure for raising and lowering said secondsection between said upper most and lowermost positions in accordancewith the rate of movement of the rudder through a fluid medium and theresultant fluid pressure on said vane means.

4. A variable area rudder comprising a bifurcated first rudder section,a second rudder section pivoted on said first rudder section in variablylapping relationship for movement in said first rudder section in aplane parallel to said first rudder section and configured anddimensioned to provide a control area for the rudder substantiallycorresponding to that of the first rudder section in an uppermostposition of the second rudder section and movable to a lowermostposition wherein the control area of the rudder is increased by apredetermined ratio for control of a craft or other object at lowspeeds, and vane means on said second rudder section responsive to fluidpressure for raising and lowering said second section between saiduppermost and lowermost positions in accordance with the rate ofmovement of the rudder through a fluid medium.

5. A variable area rudder comprising a first rudder section, a secondrudder section pivotally connected to said first rudder section invariably lapping relationship for movement in a plane parallel thereto,said second rudder section including a pair of plates connected inspaced parallel relation such as to receive said first rudder section inproximate relation therebetween and dimensioned to afford substantiallythe same control area as the first rudder section in an uppermostposition thereof, and a combined control area with said first ruddersection increased by a predetermined ratio in a lowermost position ofsaid second rudder section, and vane means responsive to fluid pressurethereagainst and fixedly secured on said second rudder section formoving said second rudder section between said uppermost position andsaid lowermost position in accordance with the relative rate of movementof the rudder through a fluid medium and the resultant fluid pressure onsaid vane means.

6. In a variable area rudder, a pair of rudder sections connected forvariably lapping pivotal movement in parallel planes, at vane on one ofsaid sections responsive to fluid pressure and providing pivotalmovement of said one section relative to the other of said sections inaccordance with the relative rate of movement of the rudder through afluid medium and the resultant fiuid pressure on said vane, an upwardlyarcuate slot on the other of said sections and a pin on said of onesections received in said slot and guiding the movement ot' said onesection between an uppermost position and a lowermost position relativeto said other section and maintaining the sections in said lappingrelationship.

7. In combination with a boat, a variable area rudder including a firstrudder section, means connected to said first rudder section and saidboat for turning the first rudder section about an axis to steer theboat, a second rudder section connected to the first rudder section invariably lapping relationship for pivotal movement about an axissubstantially perpendicular to the first-named axis and in a planeparallel to said first rudder section, and a vane on said second ruddersection responsive to fluid pressure and configured and dimensioned torotate said second rudder section relative to said first rudder sectionin accordance with the rate of the boat through the fluid medium and theresultant fluid pressure against said vane.

8. A variable area rudder comprising a first rudder section, a secondrudder section mounted for variably lapping coplanar movement relativeto said first rudder section and vane means on said second ruddersection responsive to fluid pressure and eflfective to afford saidrelative movement of said second rudder section relative to said firstrudder section in response to said fluid pressure.

9. A variable area rudder for steering a vessel or other device with acontrol surface proportionate to the speed of the vessel comprising, anupper rudder section, steering means connected to the upper ruddersection in supportiong relationship thereto, a lower rudder section,means pivotally connecting said lower rudder section to said upperrudder section for movement of said lower rudder section in coplanar,variably lapped relationship to said upper rudder section, and means onsaid lower rudder section responsive to fluid pressure from an ambientfluid medium to raise the lower rudder section relative to the upperrudder section and to reduce the effective steering area of the saidvariable area rudder proportionately to the speed thereof relative tothe ambient fluid medium.

10. A variable area rudder comprising an upper rudder section, a lowerrudder section, means connecting said lower rudder section to said upperrudder section in variably lapping, relatively movable and coplanarrelationship therewith and means on one of said rudder sectionsresponsive to fluid force for varying the lapping relationship of thelower rudder section to the upper rudder section proportionately to thesaid fluid force.

, 11. Ina variable area rudder, a pair of rudder sections, meansretaining said rudder sections in variably lapping relationship formovement in parallel planes and a vane on One of said sectionsresponsive to fluid pressure and providing movement of said one of saidsections relative to the other of said sections upon variation of fluidpressure thereagainst to vary the overlap between said sections inaccordance with the relative rate of movement References Cited in thefile of this patent UNITED STATES PATENTS Wees et a1 Oct. 15-, 1901 PostJuly 3, 1928 Northrop July 10, 195-1

